YouTube is testing a way for viewers to add community-sourced context to videos. The feature, called notes, will allow people to add bits of information to clarify things like whether a video is a parody or contains older footage presented as a current event.
If a note is considered helpful, you might see it pop up in a small box beneath a video. YouTube says only a “limited number” of eligible contributors can write notes for now, while third-party evaluators will rate the helpfulness of not...